Combined clutch and brake device



Feb. 21, 1939. H. J. SIEKMANN 2,148,326

COMBINED CLUTCH AND BRAKE DEVICE Filed on. 18, 1937 INVENTOR.

HAROLD lsmmmn ATTORNEY.

Patented Feb 21, 1939 UNITED STATES PATENT OFFICE COMBINED CLUTCH ANDBRAKE DEVICE Application October 18, 1937, Serial No. 169,551

14 Claims. (Cl. 192-4) Heretofo-re in combined clutch and brake devicesfriction operated means have been employed to perform the brakingfunction for arresting rotation of a power transmission when the drivingclutches are disengaged. The friction braking mechanism has proved mostunsatisfactory because of its lack of uniform efficiency of operationdue to wear of the frictional engaging parts and the effect of differentspeeds upon its accurate stopping when employed with change speedtransmissionsuch as a geared lathe headstock.

In order to avoid these inherent defects of all frictional brakes Ipropose the use of a gear pump which is automatically rendered effectiveas a 5 brake when the driving clutch is disengaged. This I accomplish byclosing off the inlet and outlet ports of the gear pump so that itspumping ears will be arrested from rotation and will thus cause theshaft which drives it, which in turn is 0 connected to the powertransmission, to be stopped from rotating. It can thus be seen that withthis arrangement friction plays no part in the braking of the rotatingparts. And furthermore, since the fluid used in such, a gear pump brakeis substantially non-compressible, the rotating member attached theretowill promptly be brought to a stop with unvarying efliciency when thegearpump brake is rendered effective.

An object of my invention is to provide a com- Cal 30 bined frictionclutch and hydraulic brake mechanism which is interlocked whereby thebrake is automatically rendered. effective when the clutch isinoperative.

Another object is to provide in a combined 5 clutch and brake device afriction clutch for connecting or disconnectingpower to a shaft to bedriven and a gear pump brake driven by said' vshaft and renderedeffective when the clutch is disengagedto arrest rotation of said shaft.

' 4 Further objects of my invention will appear from the detaileddescription of which:

Figure I is a section on the line II of Figures II and III showing theapplicatior' of my inventhe drawing in 3 45 tion toa lathe headstocktransmission.

Figure II is a section through the gear pump brake n the line 11-11 ofFigure I. l

Figure III is a section through the gear pump brake, with the gearsremoved, on the line III-J11 3 which is joumaled onanti-frlctionbearings 4 and 5 carried in the reverse gear housing 6 which in turn ismounted on the headstock I of a lathe.

, On the stub shaft 3 is formed a gear 8 which drives a gear 9 on theshaft I0 which is journaled on the anti-friction bearings I I and I2carried in the housing 6. Coaxial with the stub shaft 3 is journaled thedriveshaft I3 in the pilot bearing I4 in the inner end of the stub shaftand on the anti-friction bearings I5 and I6 carried in the headstock I.Journaled on the shaft I3 on its bearing portion I1 is a gear I8 whichis driven through an idler gear (not shown) from the gear I9 fixed onthe shaft I II. It can thus be seen that when the pulley I and stubshaft 3 are rotated, gear I8 will be rotated on the shaft I3 in theopposite direction.

Associated with the stub shaft 3 and its gear 8 is a multiple discclutch 20, which, when actuated by movement of the operating spool 2I onthe shaft I3 will cause the shaft I3 to bedirectly driven from the shaft3 and, of course, in the same direction. A similar multiple disc clutch22 is associated with the gear I8 which, when actuated by the spool 2Iwill cause the gear l8 to drive the shaft I3 in the opposite directionfrom that of the shaft 3. These clutches and 22 are alternately renderedeffective or both inefiective by axial movement of the spool 2| on theshaft I3. This is accomplishedby the usual yoke 23 carried on the rockshaft 24 in the housing 6 which engages in the-annular slot 25 in thespool 2I, suitable operating leverage being applied to the rock shaft 24formanipulating it. Suitable gearing 2B, 21 and "28 fixed on the driveshaft I3 engages the gearing 29, 30 and 3I to deliver power to theheadstock transmission in a usual manner.

In connection with the mechanism just described, I provide means forstopping rotation of the drive shaft I3 when the clutches 20 and 22 arerendered ineffective by moving the spool 2| to neutral position, asshown in Figure I. The arrangement comprises a gear pump brake having ahousing 32 fixed on a portion of the headstock 1 adjacent the bearing I6of the shaft I3. The shaft I3 is journaled in the bore 33 of the housing32 and in bearing 34 of the'cover plate 35 fixed to the housing, 32 byscrews 36. On the shaft I3 is fixed the gear 31 and is adapted to berotated by said shaft in a suitable cavity 38 formed in the housing 32,the gear 31 driving the mating pump gear 39 rotatably mounted on thestud 40 carried in the housing 32 and cover plate 35. The chamber 4Iformed by the gears 31 and 39, Figures II and III, is connected throughthe passageway 42 to the annular slot 43 formed in the bore 33 of thehousing 32. The chamber 44, Figures I and II, formed by the gears 31 and39 is connected through the passageway 45 to the annular slot 46a formedin the bore 34 of the cover plate 35. Ports 46 and 41 formed in theshaft l3 connect at all times with the respective annular slots 43 and46a so that fluid may pass between the gear pump chamber 42 and 44 andthe bore 48 formed in the shaft l3.

In the bore 48 of the shaft I3 is a plunger valve 49 having annulargrooves 50, 5| and 52 formed around its periphery which are allconnected through the respective passageways 53, 54, and 55 to a centralpassageway 56 formed in the valve 49. The valve 49 has an extension 51which extends to the left in Fig. I and has an end portion 58 throughwhich passes a pin 59 which also passes through the clutch operatingspool 2|, the pin 59 operating in slots and GI elongated axially of theshaft I3 so that when the spool 2| is shifted the plunger valve 49 willbe likewise shifted in the bore 48 of the shaft l3. The valve 49 is sodesigned that when the clutch spool 2l,.for example, is shifted to theleft, Figure I, to render the clutch 29 effective, the gear pump mayfreely circulate fluid through ports 54 and 55, and when the spool 2| isshifted to the right to render clutch 22 effective the gear pump mayfreely circulate fluid through ports 53 and 54, under these conditionsthere being no restriction to the free rotation of the shaft I3.However, when the spool 2| is shifted to neutral positionto render bothclutches 29 and 22 inoperative as shown in Figure I, the valve 49 is sopositioned as to close the ports 45 and 41 so that fluid cannot beexpelled from or sucked into the chamber 42 and 44 formed by the gears31 and 39 of the gear pump, said gears being thus held against rotationand as a result rotation of the shaft l3 will be arrested. The gear pumpbrake may be at all times kept primed with fluid from the lubricatingsystem for the headstock transmission which is deposited in thereservoir 62 which is connected to the cavity 38 in the housing 32 bythe passageway 63.

Having fully set forth and described my invention what I claim is:-

1. In a combined clutch and brake device, a friction clutch forconnecting or disconnecting power to a member to be driven, a hydraulicdynamic brake connected to said member, and means inter-connecting saidclutch and said brake whereby one or the other may be alternatelyrendered effective.

2. In a combTned clutch and brake device, a friction clutch forconnecting or disconnecting power to a shaft to be driven, a gear pumpconnected to and driven by said shaft, and means to prevent rotation ofsaid gear pump when said clutch is rendered inoperative.

3. In a combined clutch and brake device, a friction clutch forconnecting or disconnecting power to a shaft to be driven, a gear pumpconnected to and driven by said shaft, means to permit said gear pump tofreely circulate fluid between its inlet and exhaust ports when saidclutch has power connected to said shaft, and means for preventing saidfluid circulation by said gear pump when said clutch is inoperative.

4. In a combined clutch and brake device, a friction clutch forconnecting or disconnecting power to a shaft to be driven, means foractuating said clutch, a gear pump connected to and driven by saidshaft, means to permit said gear pump to freely circulate fluid betweenits inlet and exhaust ports, and means operated by the means foractuating said clutch to prevent said fluid circulating by said gearpump when said clutch is inoperative.

5. In a combined clutch and brake device, a friction clutch forconnecting or disconnecting power to a shaft to be driven, a gear pumpconnected to and driven by said shaft, a valve connected to the inletand exhaust ports of said pump, said valve being adapted to connect saidports to permit said pump to freely circulate fluid between them 'or toclose off said ports to prevent rotation of said pump, and means toactuate said valve to close off said ports when said clutch is renderedinoperative.

6. In a combined clutch and brake device, a friction clutch forconnecting or disconnecting power to a shaft to be driven, a gear pumpconnected to and driven by said shaft, a valve connected to the inletand exhaust ports of said pump, said valve being adapted to connect saidports to permit said pump to freely circulate fluid between them or toclose off said ports to prevent rotation of said pump, means connectedto said pump to keep it properly primed with fluid, and means to actuatesaid valve to close off said ports when said clutch is renderedinoperative.

7*. In a machine tool transmission, a driving member, a driven member,reversing gearing associated with said members, clutches for connectingsaid driving member to said driven member for alternately rotating it inone direction or the other, a gear pump driven by said driven member, avalve connected to the inlet and exhaust ports of said pump, said valvebeing adapted to connect said ports to permit said pump to freelycirculate fluid between them or to close off said ports to preventrotation of said pump, and common means for alternately rendering saidclutches and said gear pump effective for driving or arresting movementof said driven member.

8. In a machine tool transmission, a driving shaft, a driven shaft, apair of clutches associated with said driven shaft, reversing gearingconnecting said driving shaft to said clutches whereby one of saidclutches causes said driven shaft to rotate in the same direction assaid driving shaft when rendered operative and said other clutch causessaid driven shaft to rotate in the opposite direction from saiddriving'shaft when it is rendered effective control means for renderingone or the other or both of said clutches inoperative, a gear pumpdriven by said driven shaft, control means for the inlet and exhaustports of said gear pump whereby said pump may freely circulate fluidbetween said ports or said ports may be closed off to prevent rotationof said driven shaft, and inter-connecting means between said controlmeans for said clutches and said control means for said gear pumpwhereby said gear pump is rendered effective to stop rotation of saiddriven shaft when both of said clutches are rendered inoperative.

9. In a machine tool transmission, a driving shaft, a driven shaft, aclutch for engaging and disengaging said shafts, a gear pump brakeconnected to said driven shaft for arresting rotation of said drivenshaft when said driving shaft is disengaged therefrom, means connectingsaid driven shaft to said transmission, and means for supplying fluid tosaid gear pump brake from the lubricating system for said transmission.

ports of said pump to said bore and a plunger valve in said bore forinter-connecting or closing off said passageways.

11. In a combined clutch and brake device, a

clutch for connecting or disconnecting a source of power to or from ashaft to be rotated, a gear pump having one of its gears mounted on saidshaft whereby said shaft drives said gear pump, an axial bore in saidshaft, passageways connecting inlet and exhaust ports of said pump tosaid here, anda plunger valve in said bore for interconnecting orclosing off said passageways.

12. In a power transmission, a driving member, means for rendering saiddriving means op- 20 erative or inoperative, a hydraulic dynamic brakeconnected to said member, and means for rendering said brake effectivewhen said driving member is rendered inoperative for arresting thedriving action of said member.

13. In a power transmission, a prime mover, means for rendering saidprime mover operative or inoperative, a hydraulic gear pump brakeconnected to said prime mover, and means for rendering said brakeeffective when said prime mover is rendered inoperative for arrestingthe movement of said prime mover.

14. In a power transmission, a reversible source of power, means forreversing and for of power, and means for rendering said brake eflectivewhen said source 0! power is rendered inoperative.

HAROLD J. SIEKMA'NN.

